Mark Twain IS 239 School for the Gifted and Talented

Karen Ditolla, Principal

Name:______Date:______

8______ID______Ms. Baraquia

3rd Quarter Project

Family Tree (Pedigree)

Due date:______

Introduction:

A pedigree is a family tree that shows the relationships among family members and traces a specific genetic trait within the family. It is a “shorthand” way to represent the members of a family.

By following a few guidelines and using what you have learned in class about heredity and dominant and recessive traits make a pedigree chart for your family. You might even be able to find a pattern in the way a family characteristic is inherited.

Directions:

1. Using a poster board, create your family pedigree of one particular trait. (Traits are listed below.) Include the following:

  • Use the designated pedigree symbols and a legend

first names for all members and add a photo of each member

  • A title detailing what trait you will explore
  • Indicate each member’s allele, homozygous and/or heterozygous.
  • Indicate whether the trait is dominant or recessive.
  • Create a Punnett square of 2 people (indicate their names) with known genotypes. What are the possible offspring’s genotypes and phenotypes?
  • Indicate the genotype of each person (If there are several possible genotypes, put a question mark for that allele.) Example: Tongue roller (T?)

Possible traits:

TraitDominantRecessive

Eyelash length long (1 cm or more)short (less than 1 cm)

Widow’s peakwidow’s peak straight hairline

DimplesDimples No dimples

Freckles FrecklesNo freckles

Ear lobesFree ear lobesAttached

Hair on middle digitHair on middle digitNo hair on middle digit

Hand use Right-handedLeft-handed

Tongue roller Tongue rollerNon-tongue roller

Height Short Tall

Females: less than 5’75’7 or above

Males: less than 5’105’10 or above

Curved ThumbHitchhiker thumbStraight Thumb

2. Remember to be creative! Your pedigree will identify:

a Males & females

b. How people are related

c. Who has the trait and who does not

3. Once your pedigree is complete, attach your paragraph. You should follow these criteria for the paragraph.

  • Type a strong and well-written paragraph (6+ sentences) explaining your reasoning ( tell me how you know),
  • Include examples from your pedigree to make your argument for dominant or recessive.

EXAMPLE PARAGRAPH:

EXPLAINING IF TRAIT IS DOMINANT OR RECESSIVE

Crim Family Widow’s Peak Pedigree

I examined my family’s pedigree and researched the Widow’s peak trait and have determined that the trait is a recessive one. To figure this out, I first looked at my pedigree. You will see that John and Vickie both have the trait, and so do all five of their children. I also noticed that Grandma & Grandpa Zoelle both had it, and so did all eleven of their children. I was not certain that it was recessive, because this pattern could be shown if the trait is dominant and John, Vickie, and Grandma and Grandpa Zoelle were all

homozygous dominant. However, I looked up the trait in our textbook, and according to the book the trait is recessive.

**This is an example only. Be sure to write your own paragraph! Do not copy this sample!**